Battery grid casting machines conventionally employ a valve mechanism for dispensing a predetermined amount of molten metal into a mold-filling ladle during each cycle of the machine. The ladle is then tipped to pour the charge of molten metal into the cavity of the closed mold. Valve mechanisms of this type must be capable of operating freely without undue friction so as to dispense the requisite charge of molten metal at the proper time. This is particularly true where the quantity of metal dispensed is controlled by opening the valve a predetermined extent for a predetermined time period. With some valve constructions, this is difficult to achieve since the temperature of the molten metal is extremely high and tends to produce distortions and cause misalignment and malfunctioning of the valve. It thus becomes important that such valves be constructed so that their proper functioning is not adversely affected by relatively high temperatures.
In an attempt to meet the above objectives, numerous valves have been proposed which have provided a valve member or ball which is laterally movable relative to the supply nozzle to thereby insure proper alignment and hence proper closure of the valve. An example of such constructions is disclosed in U.S. Pat. Nos. 3,877,620 and 4,022,356.
While the known valve constructions, such as those illustrated in the above patents, have tended to minimize the problem of distortion and misalignment, nevertheless these valve constructions have possessed other disadvantages which have significantly interfered with the desired and efficient operation of the battery grid casting machine. More specifically, the valve member in the known valve constructions has been subject to the problem of oxidation inasmuch as a substantial portion of the valve member is exposed to the air and gases which are supplied to the valve housing during that portion of the cycle when the valve member is closed. These hot gases, and the intermittent exposure of the valve member to the molten metal, thus results in oxidation whereby oxides and deposits collect on the valve member and hence interfere with the proper seating thereof with the supply nozzle. This thus necessarily requires substantial maintenance of the valve assembly, and often requires replacing the valve member. This in itself creates substantial difficulty in many known valve constructions, since the disassembly and replacement of the valve member is a difficult and time-consuming task.
Accordingly, it is an object of the present invention to provide an improved valve mechanism for a battery grid casting machine, which valve mechanism overcomes the above disadvantages.
More specifically, the present invention relates to an improved valve mechanism, as aforesaid, which permits a predetermined quantity of molten metal to be periodically supplied to a grid casting machine, which valve mechanism in turn employs a valve member which is continuously immersed and surrounded by the molten metal so as to prevent oxidation and hence build-up of deposits thereon.
A further object is to provide a valve mechanism, as aforesaid, wherein the valve member is supported for limited sideward displacement relative to the supply nozzle to thereby insure proper alignment therebetween at all times, thereby compensating for distortions caused by high temperatures and the like.
Still a further object is to provide an improved valve mechanism, as aforesaid, wherein an upwardly opening dispenser cup is horizontally movably supported within an interior chamber defined within a tubular housing, which dispenser cup has the valve member positioned in the bottom thereof and disposed for cooperation with the lower end of the supply nozzle, whereby a predetermined quantity of molten metal is maintained in the cup at all times to thereby completely surround and immerse the valve member, both when the valve mechanism is opened and closed.
Another object is to provide an improved valve mechanism, as aforesaid, which can be efficiently and easily disassembled, and reassembled, to permit any required maintenance or repair of the valve assembly while requiring a minimum amount of labor and time and hence a minimum shutdown of the casting machine.
Other objects and purposes of the invention will be apparent to persons familiar with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings.